Abstract:

For a storage system which holds backup data of a first data storage
extent in one or more second data storage extents in use of a first
backup method, a backup status in a first backup method in a prescribed
period is acquired and a first backup performance in a first backup
configuration is computed based on this backup status. Meanwhile, a
second backup performance in a second backup configuration is estimated
based on a prescribed assumption in a prescribed period. Information is
outputted based on the computed first backup performance and the
estimated second backup performance.

Claims:

1. A computer which is connected to a storage system, the storage system
comprises a plurality of data storage extents, writes write-data
conforming to a write request to a first data storage extent specified in
the write request, and retains backup data of the first data storage
extent in one or more second data storage extents using a first backup
method, the computer comprising:an acquisition module for acquiring a
backup status in use of the first backup method at a prescribed period;a
computation module for computing a first backup performance using a first
backup configuration, which is defined by a first corresponding
relationship between the first data storage extent and the one or more
second data storage extents, and the first backup method, based on the
acquired backup status;an estimation module for estimating a second
backup performance using a second backup configuration, which is defined
by a second corresponding relationship between the first data storage
extent and one or more second data storage extents, and a second backup
method, based on a prescribed assumption in the prescribed period; andan
output module for outputting information based on the computed first
backup performance and the estimated second backup performance.

2. The computer according to claim 1, further comprising a reception
module for receiving a write-amount, which is the amount of write-data at
each point-in-time interval for the first data storage extent in the
storage system, whereinthe acquisition module acquires respective write
times at which data has been written to the second data storage extent in
use of the first backup method at the prescribed period;the computation
module computes a first data protection period, which is a time period
from the oldest time at which backup data is recoverable using the first
backup method until a targeted time, for the respective targeted times in
the prescribed period, based on the respective acquired write times;
andthe estimation module estimates a second data protection period, which
is a time period from the oldest time at which backup data is recoverable
using the second backup method until a targeted time, for the respective
targeted times in the prescribed period, based on the write-amount at
each of the received point-in-time interval.

3. The computer according to claim 2, whereinthe second backup
configuration is a CDP backup configuration executed by a backup method
conforming to CDP technology;the second data storage extents in the
second backup configuration include a base data storage extent, in which
base data that is a replication of data stored in the first data storage
extent is stored, and a journal storage extent, in which a journal that
is information related to a write history in the first data storage
extent and that is reflected in the base data, is stored; andthe
estimation module estimates an amount of stored journals, which is an
amount of journals stored in the journal storage extent, for the
respective targeted times at the prescribed period based on the
write-amount at each received point-in-time interval, and estimates the
second data protection period for the respective targeted time based on
the write-amount at each the received point-in-time interval and the
amount of stored journals at the respective targeted times.

4. The computer according to claim 3, wherein an estimation equation for
the amount of stored journals CT at the respective targeted times
is:CT=CT-1+(IT-OT)where, CT-1 is an amount of
stored journals at an immediately prior targeted time; IT is an
input amount, which is an amount of journals inputted to the journal
storage extent at a targeted point-in-time interval from the immediately
prior targeted time until the current targeted time; and OT is an
output amount, which is an amount of journals deleted from the journal
storage extent at the targeted point-in-time interval.

5. The computer according to any one of claims 1 through 4, whereinthe
reception module further receives a storage capacity of the one or more
second data storage extents in the first backup configuration; andthe
prescribed assumption is that the one or more second data storage extents
in the second backup configuration have the same storage capacity as the
storage capacity of the one or more second storage extents in the first
backup configuration.

6. The computer according to claim 5, further comprising an assumption
receiving module for receiving from a user an assumption input that
differs from the prescribed assumption, whereinthe estimation module
estimates the second backup performance based on the different assumption
inputted from the user.

7. The computer according to any one of claims 1 through 6, whereinthe
first backup performance, in addition to a first data protection period,
has at least one of a storage capacity of one or more second data storage
extents in the first backup configuration, continuity of backup times for
recoverable backup data, and a fluctuation range of the first data
protection period; andthe second backup performance, in addition to a
second data protection period, has at least one of a storage capacity of
one or more second data storage extents in the second backup
configuration, continuity of backup times for recoverable backup data,
and a fluctuation range of the second data protection period.

8. The computer according to claim 7, further comprising: a scoring module
for carrying out scoring, whereinthe scoring module computes a score for
a determination item of the first data protection period, and at least
one determination item from among respective determination items, in the
first backup configuration, of the storage capacity of one or more second
data storage extents, the continuity of backup times for recoverable
backup data, and the fluctuation range of the first data protection
period, based on the result of comparing a first backup performance
corresponding to the determination item with a reference value, and/or
the result of comparing the first backup performance corresponding to the
determination item with a second backup performance; andcomputes a score
for a determination item of the second data protection period, and at
least one determination item from among respective determination items,
in the second backup configuration, of the storage capacity of one or
more second data storage extents, the continuity of backup times for
recoverable backup data, and the fluctuation range of the second data
protection period, based on the result of comparing the second backup
performance corresponding to the determination item with a reference
value, and/or the result of comparing the first backup performance
corresponding to the determination item with the second backup
performance.

9. The computer according to claim 8, wherein the scoring module
calculates a total score, which is calculated on the basis of the
respective scores, and/or not less than two scores of each backup
configuration, based on a weighting coefficient for each determination
item.

10. The computer according to any one of claims 1 through 9, wherein the
output module displays the computed first backup performance alongside
the estimated second backup performance.

11. The computer according to any one of claims 1 through 10, further
comprising: a determination module for comparing the computed first
backup performance with the estimated second backup performance, and
determining that the superior of these performance is the appropriate
backup configuration, whereinthe output module outputs information based
on the determination result as information based on the computed first
backup performance and the estimated second backup performance.

12. The computer according to claim 11, wherein information based on the
determination result is an instruction for changing from the first backup
configuration to the second backup configuration, and is information
which is sent to the storage system.

13. A computer system, comprising:a storage system, which comprises a
plurality of data storage extents, and which writes write-data conforming
to a write request to a first data storage extent specified by the write
request, and holds backup data of the first data storage extent in one or
more second data storage extents in use of a first backup method; anda
computer which is connected to the storage system,the computer
comprising:an acquisition module for acquiring a backup status in the
first backup method in a prescribed period;a computation module for
computing a first backup performance in a first backup configuration,
which is defined by a first corresponding relationship between the first
data storage extent and the one or more second data storage extents, and
the first backup method, based on the acquired backup status;an
estimation module for estimating a second backup performance in a second
backup configuration, which is defined by a second corresponding
relationship between the first data storage extent and one or more second
data storage extents, and a second backup method, based on a prescribed
assumption in the prescribed period; andan output module for outputting
information based on the computed first backup performance and the
estimated second backup performance.

14. A backup configuration design support method, comprising the steps
of:acquiring the backup status in the first backup method in a prescribed
period for a storage system, which comprises a plurality of data storage
extents, and which writes write-data conforming to a write request to a
first data storage extent specified by the write request, and holds
backup data of the first data storage extent in one or more second data
storage extents in use of a first backup method;computing a first backup
performance in a first backup configuration, which is defined by a first
corresponding relationship between the first data storage extent and the
one or more second data storage extents, and the first backup method,
based on the acquired backup status;estimating a second backup
performance in a second backup configuration, which is defined by a
second corresponding relationship between the first data storage extent
and one or more second data storage extents, and a second backup method,
based on a prescribed assumption in the prescribed period; andoutputting
information based on the computed first backup performance and the
estimated second backup performance.

15. The computer according to claim 4, wherein IT is either
WT+W'T-1, Pj, or V-CT-1, WT is a write-amount at
a targeted point-in-time interval, W'T-1 is an amount of unwritten
journal in the journal storage extent at the immediately prior targeted
point-in-time interval, Pj is journal write performance at the
targeted point-in-time interval calculated by multiplying the amount of
journals capable of being written to the journal storage extent per
module of time by the targeted point-in-time interval, and V is a storage
capacity of the journal storage extent, anda computation equation for the
amount of unwritten journals at the targeted point-in-time interval
W'T is:W'T=(WT+W'T-1)-IT.

16. The computer according to claim 5, wherein IT is the smallest
value from among WT+W'T-1, Pj, and V-CT-1.

17. The computer according to claim 4, wherein OT is either
CT-1+IT-H, or PD, H is a threshold for determining if a
journal is to be reflected in base data of a base data storage extent
based on the amount of journals stored inside the journal storage extent,
and PD is journal deletion performance.

18. The computer according to claim 17, wherein PD is PJ-IT
when PJ<PB, and is the largest value of PJ-IT and
PB when PJ>PB, andPB is journal reflection
performance at the targeted point-in-time interval calculated by
multiplying the amount of journals capable of being reflected in the base
data storage extent per module of time by the targeted point-in-time
interval.

19. The computer according to claim 17 or 18, wherein OT is the
smallest value of the largest value of O and CT-1+IT-H, and
PD.

Description:

CROSS-REFERENCE TO PRIOR APPLICATION

[0001]This application relates to and claims the benefit of priority from
Japanese Patent Application number 2007-241677, filed on Sep. 19, 2007,
the entire disclosure of which is incorporated herein by reference.

BACKGROUND

[0002]The present invention generally relates to technology for supporting
the construction of a configuration related to a backup executed by a
storage system.

[0003]Technology for backing up data (for convenience sake, referred to as
"source data" hereinafter) in preparation for a failure or human error
that results in the loss of source data is being widely applied in
computer systems.

[0004]One known backup method involves creating a replicate (hereinafter,
replicated data) at a certain time for backup-targeted source data, and
storing this replicated data in a storage extent (for example, in a
secondary logical volume that constitutes a pair with a primary logical
volume, hereinafter referred to as "SVOL") that is different from the
storage extent in which the source data is stored (for example, a primary
logical volume, hereinafter referred to as "PVOL"). Replicated data is
either created regularly on the basis of a preset schedule, or is created
as deemed necessary in accordance with a user indication.

[0005]Further, another known backup method conforms to CDP (Continuous
Data Protection) technology, which makes source data at an arbitrary
point in time recoverable for a certain limited period of time. In this
technology, information denoting a history related to the updating of
source data (hereinafter, a journal) is acquired at source data updating,
and this journal is stored in a storage extent that is different from the
PVOL (for example, a logical volume, hereinafter referred to as "JVOL").
A replicate of the source data of prior to journal acquisition
(hereinafter, "base data") is also created, and this is stored in a
storage extent that is again different from the storage extent in which
the source data and journal are stored (for example, a logical volume,
hereinafter referred to as "BVOL"). When a data recovery request
specifying an arbitrary specified time is received, one or more journals
acquired from the BVOL creation time (base data acquisition time) up to
this specified time are reflected in order in the BVOL, thereby
recovering the source data of the specified time inside the BVOL (That
is, the base data is updated to the source data of the specified time.).

[0006]To construct a backup configuration in a storage system for carrying
out a backup using a backup method, which conforms to CDP technology
(hereinafter, a CDP configuration), it is necessary to design beforehand
a data protection period (a period from a prescribed time to the oldest
time at which data is recoverable) and a JVOL storage capacity. Japanese
Patent Laid-open No. 2007-140746 discloses technology for computing the
required JVOL storage capacity based on user design conditions (target
recovery point, target recovery time, journal storage period, and so
forth) and measured data regarding the write status of the data.

[0007]However, in a storage system that is already in operation, it is
assumed that some sort of backup method already exists prior to
constructing a new backup configuration (for example, a CDP
configuration). Determining the propriety of migrating from an existing
backup method to another backup method is difficult. Japanese Patent
Laid-open No. 2007-140746 discloses CDP configuration design technology,
but does not offer a disclosure related to determining whether or not it
is appropriate to migrate from an existing backup configuration to the
CDP configuration.

SUMMARY

[0008]Therefore, an object of the present invention is to make it possible
to determine whether or not it is appropriate to migrate from an existing
backup configuration to a different backup configuration.

[0009]Other objects of the present invention should become clear from the
following explanation.

[0010]For a storage system, which retains backup data of a first data
storage extent in one or more second data storage extents using a first
backup method, the backup status in the first backup method at a
prescribed period is acquired, and a first backup performance in a first
backup configuration is computed based on this backup status. Meanwhile,
a second backup performance in a second backup configuration is estimated
based on a prescribed assumption at a prescribed period. Information
based on the computed first backup performance and the estimated second
backup performance is outputted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows an example of the constitution of a computer system in
a first embodiment of the present invention;

[0012]FIG. 2 shows an example of the constitution of a replicated data
management table stored by the storage system;

[0013]FIG. 3 shows an example of a data protection period in a fixed-time
backup configuration;

[0014]FIG. 4 is a diagram of data protection period calculation method in
a CDP backup configuration;

[0015]FIG. 5 shows an example of the transition of a data protection
period in a CDP backup configuration;

[0016]FIG. 6 shows an example of the constitution of a determination
criteria management table stored by a management computer;

[0018]FIG. 8 shows an example of the flow of scoring for determination
items;

[0019]FIG. 9 shows an example of the constitution of a monitoring
information management table stored by the management computer;

[0020]FIG. 10 shows an example of the constitution of a performance
information management table stored by the management computer;

[0021]FIG. 11 shows the flow of processing carried out by the first
embodiment;

[0022]FIG. 12 shows an example of a determination support screen displayed
by the management computer;

[0023]FIG. 13 shows an example of the constitution of a computer system in
a second embodiment of the present invention; and

[0024]FIG. 14 shows an example of the constitution of a CDP management
table stored by the storage system in the second embodiment of the
present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025]In Embodiment 1, a storage system comprises a plurality of data
storage extents, writes write-data conforming to a write request to a
first data storage extent specified in this write request, and retains
the backup data of this first data storage extent in one or more second
data storage extents in use of a first backup method. A computer
comprises an acquisition module for acquiring a backup status using the
first backup method at a prescribed period for this storage system; a
computation module for computing a first backup performance using a first
backup configuration (a configuration defined by a first corresponding
relationship between the first data storage extent and the one or more
second data storage extents, and a first backup method) based on the
acquired backup status; an estimation module for estimating a second
backup performance using a second backup configuration (a configuration
defined by a second corresponding relationship between the first data
storage extent and one or more second data storage extents, and a second
backup method) based on a prescribed assumption for the above-mentioned
prescribed period; and an output module for outputting information based
on the computed first backup performance and the estimated second backup
performance.

[0026]The estimation module can assume that the first data storage extent
in the second backup configuration is the first data storage extent in
the first backup configuration, and can also assume that the second data
storage extent (and/or the storage capacity of one or more second data
storage extents) in the second backup configuration is the second data
storage extent (and/or the storage capacity of one or more second data
storage extents) in the first backup configuration.

[0027]In Embodiment 2 according to Embodiment 1, the computer further
comprises a reception module for receiving a write-amount, which is the
amount of write-data at each point-in-time interval for the first data
storage extent in the storage system. The acquisition module acquires the
respective write times at which data was written to a second data storage
extent in use of the first backup method for a prescribed period. The
computation module computes a first data protection period, which is a
time period from the oldest time at which backup data is recoverable
using the first backup method until a targeted time, for the respective
targeted times in a prescribed period, based on the respective acquired
write times. The estimation module estimates a second data protection
period, which is a time period from the oldest time at which backup data
is recoverable using the second backup method until a targeted time, for
the respective targeted times in a prescribed period, based on the
write-amount at each received point-in-time interval.

[0028]In Embodiment 3 according to Embodiment 2, the second backup
configuration is a CDP backup configuration executed by a backup method
conforming to CDP technology. The second data storage extents in the
second backup configuration include a base data storage extent, in which
base data which is a replication of data stored in the first data storage
extent is stored, and a journal storage extent, in which a journal which
is information related to the write history for the first data storage
extent and which is reflected in the base data, is stored. The estimation
module estimates the amount of stored journals, which is the amount of
journals stored in the journal storage extent, for the respective
targeted times in a prescribed period based on the write-amount at each
received point-in-time interval, and estimates a second data protection
period for the respective targeted times based on the write-amount at
each received point-in-time interval and the amount of stored journals at
the respective targeted times.

[0029]In Embodiment 4 according to Embodiment 3, the estimation equation
for the amount of stored journals CT at the respective targeted
times is:

CT=CT-1+(IT-OT)

CT-1 is the amount of stored journals at the immediately prior
targeted time. IT is an input quantity, which is the amount of
journals inputted to the journal storage extent at a targeted
point-in-time interval from the immediately prior targeted time until the
current targeted time. OT is an output quantity, which is the amount
of journals deleted from the journal storage extent at a targeted
time-period interval.

[0030]In Embodiment 5 according to any of Embodiments 2 to 4, the
reception module further receives the storage capacity of one or more
second data storage extents in the first backup configuration. The
above-mentioned prescribed assumptions include the assumption that the
one or more second data storage extents in the second backup
configuration have the same storage capacity as the storage capacity of
the one or more second storage extents in the first backup configuration.

[0031]In Embodiment 6 according to Embodiment 5, the computer can further
comprise an assumption receiving module for receiving from a user an
assumption input that differs from the above-mentioned prescribed
assumption. In this case, the estimation module estimates the second
backup performance based on a different assumption inputted from the
user. More specifically, for example, the assumption receiving module has
the storage capacity of one or more second data storage extents in the
second backup configuration, and receives from the user a storage
capacity input, which differs from the storage capacity of the one or
more second data storage extents in the first backup configuration. The
estimation module estimates the second backup performance based on the
above-mentioned different storage capacity inputted from the user. In
this embodiment, the output module can display a second backup
performance estimated based on a pre-change assumption alongside a second
backup performance estimated based on a post-change assumption.

[0032]In Embodiment 7 according to any of Embodiments 1 to 6, the first
backup performance, in addition to a first data protection period, has at
least one of a storage capacity of one or more second data storage
extents in the first backup configuration, continuity of backup times for
recoverable backup data, and a fluctuation range of the first data
protection period. The second backup performance, in addition to a second
data protection period, has at least one of a storage capacity of one or
more second data storage extents in the second backup configuration,
continuity of backup times for recoverable backup data, and the
fluctuation range of the second data protection period.

[0033]In Embodiment 8 according to Embodiment 7, the computer further
comprises a scoring module for carrying out scoring. The scoring module
computes a score for the determination item of the first data protection
period, and at least one determination item from among the respective
determination items of the storage capacity of one or more second data
storage extents in the first backup configuration, the continuity of
backup times for recoverable backup data, and the fluctuation range of
the first data protection period, based on the result of comparing the
first backup performance corresponding to the determination item with a
reference value, and/or the result of comparing the first backup
performance corresponding to the determination item with the second
backup performance. Further, the scoring module computes a score for the
determination item of the second data protection period, and at least one
determination item from among the respective determination items of the
storage capacity of one or more second data storage extents in the second
backup configuration, the continuity of backup times for recoverable
backup data, and the fluctuation range of the second data protection
period, based on the result of comparing the second backup performance
corresponding to the determination item with a reference value, and/or
the result of comparing the first backup performance corresponding to the
determination item with the second backup performance.

[0034]In Embodiment 9 according to Embodiment 8, the scoring module
calculates a total score, which is calculated on the basis of the score
of each determination item, and/or not less than two scores of each
backup configuration, based on a weighting coefficient for each
determination item.

[0035]In Embodiment 10 according to any of Embodiments 1 to 9, the output
module displays the computed first backup performance alongside the
estimated second backup performance.

[0036]In Embodiment 11 according to any of Embodiments 1 to 10, the
computer further comprises a determination module. The determination
module compares the computed first backup performance with the estimated
second backup performance, and determines that the superior of these
performance is the appropriate backup configuration. The output module
outputs information based on the determination result as information
based on the computed first backup performance and the estimated second
backup performance.

[0037]In Embodiment 12 according to Embodiment 11, information based on
the above-mentioned determination result is an instruction for changing
from the above-mentioned first backup configuration to the
above-mentioned second backup configuration, and is information, which is
sent to the storage system.

[0038]At least two or more of the above-described Embodiments 1 to 12 can
be combined. Further, at least one of the above-described acquisition
module, computation module, estimation module, output module, reception
module, assumption receiving module, scoring module and determination
module can be constructed from hardware, a computer program, or a
combination of these (for example, a portion of these modules can be
realized via computer programs, and the remainder can be realized using
hardware). A computer program is executed by being read into a prescribed
processor. Further, a storage area residing in a hardware resource, such
as a memory, can be arbitrarily used when performing information
processing, which is carried out by reading a computer program into the
processor. Further, a computer program either can be installed in the
computer from a CD-ROM or other such recording media, or can be
downloaded to the computer via a communication network.

[0039]The first and second embodiments of the present invention will be
explained below by referring to the figures. The first embodiment is
constituted such that, when a fixed-time backup configuration has already
been constructed in the storage system, but a CDP backup configuration
has not been constructed in the storage system, it is easy for the user
(for example, the administrator) to determine whether it is appropriate
to migrate from the fixed-time backup configuration to the CDP backup
configuration. According to the fixed-time backup configuration,
replications of data at certain backup acquisition times in a data
storage extent (for example, a primary logical volume) are regularly
stored in a replicated data storage extent, which has the oldest
generation (the backup acquisition time that is the furthest in the past)
of one or more replicated data storage extents (for example, secondary
logical volumes) prepared from this data storage extent. Conversely, the
second embodiment is constituted such that, when a CDP backup
configuration has already been constructed in the storage system, but a
fixed-time backup configuration has not been constructed in the storage
system, the user can easily determine the appropriateness of migrating
from the CDP backup configuration to the fixed-time backup configuration.

First Embodiment

[0040]FIG. 1 is a diagram showing the constitution of a computer system in
the first embodiment of the present invention.

[0041]A host computer 400 is connected to a storage system 100 via a data
I/O network 101, and issues an I/O request (a data write request and a
data read request) to the storage system 100. The data I/O network 101 is
a communication network, such as a fibre channel or IP network, and, for
example, is a SAN (Storage Area Network).

[0042]There is a management computer 300, which carries out management
related to the data communications of the storage system 100 and the host
computer 400. The management computer 300 is connected to the storage
system 100 via a management network 102. The management network 102 is a
communication network, such as an IP network, and, for example, is a LAN
(Local Area Network). Further, this management network 102 can also be a
constitution, which shares the same elements with the above-mentioned
data I/O network 101. The management computer 300 and storage system 100
send and receive information to and from one another via this management
network 102. Hereinafter, the information transceived between the
management computer 300 and storage system 100 will be referred to as
"management information".

[0043]Further, the storage system 100 has a connector (for example, a bus
or switch) 160 on the inside, and a storage apparatus 110, program memory
130, cache memory 140, CPU (Central Processing Unit) 150, data I/O
interface 170, and management interface 180 are respectively connected to
the connector 160. Communications with machines outside the storage
system 100 are carried out via the data I/O interface 170 and management
interface 180.

[0044]The cache memory 140, for example, is a volatile memory. The cache
memory 140 temporarily stores data, which is written to a storage
apparatus 110 (for example, a data storage extent 120) in accordance with
a write request (write-data), and data, which is read out from a storage
apparatus 110 in accordance with a read request (read-data).

[0045]The storage apparatus 110, for example, is constituted from one or
more storage media drives (for example, hard disk drives, flash memory
drives, and so forth). A plurality of logical volumes is created based on
the storage space of the storage apparatus 110. As a logical volume,
there is a data storage extent 120 specified by a write request or a read
request from the host computer 400, and a replicated data storage extent
121 for storing replicated data (backup data), which is the replication
of data at specified times in a data storage extent 120. Furthermore,
there is no need to restrict the capacity or number of data storage
extents 120 and replicated data storage extents 121.

[0046]The program memory 130, for example, is a nonvolatile memory, and
stores the variety of programs and information responsible for operating
the storage system 100. The various computer programs are executed by the
CPU 150. The computer programs include a management information
input/output program 131, a data replication program 132, and a data
input/output monitoring program 133, and the information includes a
replicated data management table 134. The computer programs and table
stored in the program memory 130 will be explained hereinbelow.
Furthermore, hereinafter, when a computer program is the subject, it is
supposed that processing is actually being carried out by the CPU, which
executes this computer program.

[0047]The management information input/output program 131 sends and
receives management information between the storage system 100 and the
management computer 300. Further, the management information input/output
program 131 transfers received management information to either a program
or table inside the program memory 130. For example, the management
information input/output program 131, upon receiving a monitoring data
acquisition request from the management computer 300, transfers this
request to the data input/output monitoring program 134. Furthermore, as
will be explained by referring to FIG. 11, management information
includes a monitoring data acquisition request, amount of write-data at
each point-in-time interval, information recorded in the replicated data
management table 135, and a migration indication.

[0048]The data replication program 132 stores a replicate of data inside a
data storage extent 120 at a prescribed time in a replicated data storage
extent 121. This program 132 is operated by a fixed-time backup
configuration, which is the existing backup configuration in this
embodiment. The timing at which replicated data is to be created is
indicated by either the host computer 400 or the management computer 300
(for example, by the user, who is operating this computer, or by an
automated scheduler). Further, the data replication program 132 updates
the replicated data management table 135, which will be described
hereinbelow, subsequent to the end of a data replication process. More
specifically, for example, the identifier of replicated data storage
extent 121, which is the storage destination of the replicated data, the
backup generation (the chronological order number of the backup data),
the acquisition time (the time at which the replicated data was created
and stored), and the storage capacity of this replicated data storage
extent 121 are made correspondent to the copy source data storage extent
120 of this replicated data storage extent 121 in this table 135.

[0049]The data input/output monitoring program 134 acquires
input/output-related management information from the host computer 400
relative to the monitoring-targeted data storage extent 120 in a
monitoring period described in the monitoring data acquisition request
received from the management computer 300. This management information
comprises at least the amount of write-data (hereinafter, write-amount)
received from the host computer 400 in the data acquisition interval
(point-in-time interval) described in the monitoring data acquisition
request. Further, the write-amount can also be an average value, or the
total value (total amount) of the amount of write-data in the pertinent
data acquisition interval. In the case of an average value, it is
possible to calculate the total amount by multiplying the data
acquisition interval by the average value. In addition thereto, the
maximum value and/or minimum value of the amount of write-data can also
be acquired. Furthermore, the data input/output monitoring program 134
acquires the time at which the replicated data was created for the
pertinent data storage extent 120 via the data replication program 132 in
the specified monitoring period, and the identifier of the replicated
data storage extent 121 in which replicated data was stored at this time.

[0051]FIG. 2 shows an example of the constitution of the replicated data
management table 135. Furthermore, in the following explanation, a data
storage extent and a replicated data storage extent may be denoted by the
identifier thereof instead of a reference numeral.

[0052]A field 1350 of the replicated data management table 135 records the
identifier of the replication-targeted (copy source) data storage extent
120, a field 1351 records information denoting the storage capacity of
this data storage extent 120, a field 1352 records the generation number
of the replication (backup) relative to the replication-targeted data
storage extent, a field 1353 records the identifiers of the respective
replicated data storage extents storing the acquired replicated data, a
field 1354 records information denoting the times at which the respective
replicated data were acquired, and a field 1355 records information
denoting the storage capacities of the respective replicated data storage
extents.

[0053]For example, according to FIG. 2, it is clear that there are three
generations of replicated data about data storage extent 00:01, first
generation replicated data is stored in replicated data storage extent
0A:03, second generation replicated data is stored in replicated data
storage extent 0A:02, third generation replicated data is stored in
replicated data storage extent 0A:01, and the data storage extent 00:01,
as well as the three replicated data storage extents 0A:01, 0A:02, and
0A:03 have 100 MB (megabytes) of storage capacity. The larger the
generation number, the younger the backup generation, the newest
replicated data is "01", and as the acquisition time becomes older, the
generation number increases. That is, in FIG. 2, the newest replicated
data was acquired on Jul. 19, 2007 at 00 hours 00 minutes, and the
generation number is "01". Further, the next newest replicated data was
acquired on Jul. 18, 2007 at 00 hours 00 minutes, and the generation
number increases by one to become "02". In this embodiment, generation
numbers are assigned to replicated data like this, and the largest of the
generation numbers is the number of replicated data residing in the data
storage extent 120. Accordingly, the combination of the generation number
and replicated data storage extent identifier changes with the
acquisition of replicated data. The assigning of generation numbers (for
example, the beginning value and/or order) can be a different system.

[0054]Refer to FIG. 1 once again. The management computer 300 will be
explained below.

[0055]The management computer 300 has a disk device (for example a hard
disk drive) 310 (can also be another kind of storage media drive),
program memory 320, output device 330, input device 340, CPU 350, cache
memory 360, and management interface 370, and these are connected, for
example, via a bus. The hardware configuration of the management computer
300, for example, can also be the same as that of a general-purpose
computer (a personal computer). For example, the input device 340 can be
a keyboard or mouse, and the output device 330 can be a CRT (Cathode Ray
Tube), LCD (Liquid Crystal Display), or other such display device and
video output device. Similarly, for example, the management interface 370
can be an Ethernet (registered trademark) or other such general-purpose
communication device. Further, for example, the program memory 320 can be
a magnetic storage apparatus- or semiconductor storage apparatus-based
data storage device.

[0056]The program memory 320, for example, stores a management information
input/output program 321, data collection program 322, data analysis
program 323, migration determination program 324, determination criteria
management table 325, and monitoring information management table 326.
The computer programs stored in the program memory 320 are read into and
executed by the CPU 350. Further, when the CPU 350 executes the various
computer programs, the tables stored in the program memory 320 are
arbitrarily referenced.

[0057]The programs and tables stored in the program memory 320 inside the
management computer 300 will be explained below.

[0058]The management information input/output program 321 sends and
receives management information between the management computer 300 and
the storage system 100. Further, the management information input/output
program 321 transfers management information received from the storage
system 100 to either a program or table inside the program memory 320.
That is, by executing the management information input/output program
321, the CPU 350 can store received management information in the program
memory 320, or use the management information to execute another program.

[0059]The data collection program 322 collects management information
related to the storage system 100 by way of the management information
input/output program 321. More specifically, for example, the data
collection program 322 accepts a backup configuration migration
determination request from the user, and upon receiving this request,
issues a monitoring data acquisition request to the storage system 100.
Then, in accordance with this request, the data collection program 322
receives management information acquired by the data input/output
monitoring program 134 of the storage system 100 (for example, the
above-mentioned write-amount of each data acquisition interval), and
information recorded in the replicated data management table 135 (the
number of generations of replicated data relative to the targeted data
storage extent 120, the storage capacity of the respective replicated
data storage extents, and the acquisition times of the respective
generations). A monitoring data acquisition request comprises information
(identifier of monitoring-targeted storage extent, monitoring period, and
data acquisition interval) recorded in the monitoring information
management table 326, which will be explained hereinbelow.

[0060]The data analysis program 323 uses the management information
collected by the data collection program 322, computes the data
protection period in the fixed-time backup configuration, and estimates
the data protection period when the CDP backup configuration is assumed.
The data protection period is the period during which backup data is
retained, and denotes how far back from a targeted point-in-time (for
example, the present) it is possible to recover data of a previous
point-in-time. The data analysis program 323 also calculates other
determination items mentioned in the determination criteria management
table 324, which will be described hereinbelow using FIG. 6.

[0061]The respective methods for calculating the data protection period in
the fixed-time backup configuration, and the data protection period in
the CDP backup configuration will be explained below.

[0062]<(1) Data Protection Period in Fixed-Time Backup
Configuration>

[0063]In the fixed-time backup configuration, either one or a plurality of
replicated data storage extents 121 are provided for data (source data)
of a backup-targeted data storage extent 120, and replicated data of a
specified time is stored in a replicated data storage extent 121 selected
from among this replicated data storage extents 121. For example,
according to the replicated data management table 135 shown in FIG. 2,
three replicated data storage extents 0A:01, 0A:02, and 0A:03 are
provided for one data storage extent 00:01, and replicated data acquired
at a certain backup acquisition time is stored in the replicated data
storage extent with the oldest acquisition time of these three replicated
data storage extents 0A:01, 0A:02, and 0A:03.

[0064]With this fixed-time backup configuration in view, the data
protection period of one replicated data (one generation) is calculated
using (Equation 1) below. It is supposed that time T is a time in a range
of times from the replicated data acquisition time until this replicated
data is updated by replicated data of a different time.

[0065]A data protection period, which takes all generations into account,
is the maximum value of the results of (Equation 1) calculations for a
plurality of data storage extents. That is, when the number of
generations is N, the data protection period of data (source data) stored
in the pertinent data storage extent at time T (one data storage extent
corresponding to a plurality of replicated data storage extents) is
calculated using (Equation 2) below.

[0066]For example, according to the example in the replicated data
management table 135 shown in FIG. 2, a data protection period in
accordance with the above-mentioned (Equation 2) would become:

[0067][Data Protection Period of Data Storage Extent 00:01 at Time
T]=Max(([Time T]-[0A:01 Replication Acquisition Time]), ([Time T]-[0A:02
Replication Acquisition Time]), ([Time T]-[0A:03 Replication Acquisition
Time])). FIG. 3 shows the result obtained by plotting the results of this
computation on a time axis. In FIG. 3, the broken lines show the
respective data protection periods of the three replicated data storage
extents 0A:01, 0A:02, 0A:03, and the solid line shows the data protection
period for the pertinent data storage extent 00:01.

[0068]Furthermore, in this first embodiment, the management computer 300
can determine the acquisition times of the respective generations by
receiving from the storage system 100 the information recorded in the
storage system 100-managed replicated data management table 135, but in
the second embodiment, since acquisition time such as this is not managed
by the storage system 100, it is possible to assume that a time (for
example, at 00 hours 00 minutes each day) in a point-in-time interval
(for example, daily) specified by the user is the acquisition time.

[0069]<(2) Data Protection Period in CDP Backup Configuration>

[0070]In the CDP backup configuration, for example, data storage extent
replicated data (hereinafter, called "base data") of a certain point in
time is acquired, and a journal, which was acquired at a later time than
the base data acquisition time, is stored. When recovering data of a
certain time in the past (hereinafter, specified recovery time), data at
the specified recovery time is recovered by reflecting in the base data
journals corresponding to the respective update times up until the
specified recovery time.

[0071]A journal, for example, is constituted from journal meta data and
journal data. As for journal data, for example, when a journal is a
so-called after-journal, the journal data is write-data written to a data
storage extent (that is, post-update write-data), and when a journal is a
so-called before-journal, the journal data is write-data prior to being
updated by the write-date written to the data storage extent. Journal
meta data, for example, is management data, such as the update time (when
data was written), update number, and update location (the location in
the data storage extent where a write occurred). A journal can be stored
in a journal storage extent (logical volume), which will be explained
hereinbelow, journal data can be stored in the journal storage extent,
and journal meta data can be stored in a different storage extent, such
as a memory in the storage system 100.

[0072]Reflecting a journal in the base data signifies the fact that the
journal data inside this journal is written to the update location
specified from the journal meta data inside this journal. The source data
of respective update times is sequentially restored by sequentially
reflected in the base data journals, from the oldest unreflected journal
to the journal corresponding to the specified recovery time, ultimately
recovering the source data of the specified recovery time. That is, in
the CDP backup configuration, continuous data protection is possible.

[0073]To construct a CDP backup configuration, it is necessary to
determine the storage capacity of the base data storage extent in which
the base data will be stored, and the storage capacity of the journal
storage extent in which a journal (for example, journal data only) will
be stored.

[0074]In this embodiment, the storage capacity of the base data storage
extent is the same as the storage capacity of the data storage extent 120
that constitutes the protection target. Using the example shown in FIG.
2, since the data storage extent 00:01 is 100 MB, the storage capacity of
the base data storage extent will also be 100 MB.

[0075]Then, the total storage capacity of the storage extents required for
storing base data as well as journals in the CDP backup configuration
(for convenience sake, called "backup retention capacity" hereinafter),
for example, is specified in the determination criteria management table
325, which will be explained hereinbelow using FIG. 6. The capacity
required for the storage of journals is the value obtained by subtracting
the storage capacity of the base data storage extent from the backup
retention capacity. More specifically, for example, if the backup
retention capacity is 300 MB, the storage capacity required for the
storage of journals will be the value obtained by subtracting the 100 MB
storage capacity of the base data storage extent from the 300 MB of
backup retention capacity, that is, 200 MB.

[0076]The data protection period at a certain time T is calculated based
on the transition of the write-amount relative to the protection-targeted
data storage extent 120, and the total amount of unreflected journals
(hereinafter, amount of stored journals). In the second embodiment
described below, this amount of stored journals can be the total amount
of unreflected journals actually stored in the storage system 100, and is
treated as a measured value that is acquirable from the storage system
100, but in this first embodiment, since unreflected journals are not
actually stored, the amount of stored journals is a value, which is
calculated using the below-described computational equation for
estimating amount of stored journals.

[0077]Further, the base data storage extent and the journal storage extent
do not actually exist prior to migration to the CDP backup configuration,
and it is supposed that subsequent to migrating from the existing backup
configuration to the CDP configuration the storage extents (that is, the
replicated data storage extents 121) being used in current backup
applications will be utilized. More specifically, for example, according
to the data analysis program 323 it is assumed that one of the replicated
data storage extents 0A:01, 0A:02, 0A:03 will become the base data
storage extent, and the remaining two will become the journal storage
extent.

[0078]Further, in this embodiment, it is assumed that the sizes of
write-data and a journal are 1:1. That is, it is supposed that journal
data, which is the same quantity as write-data, is written to the journal
storage extent (and it is supposed that journal meta data is stored in
another storage extent). The size of a journal can be properly estimated
in accordance with the storage system regardless of the above
assumptions.

[0079]The amount of stored journals CT stored in a journal storage
extent at a certain time T is calculated by the data analysis program 323
using the following (Equation a).

CT=CT-1+(IT-OT) (Equation a)

[0080]CT-1 denotes the amount of stored journals at the data
acquisition time (T-1) immediately prior to the time T, IT denotes
the amount of journals written in the journal storage extent at time T,
and OT denotes the amount of journals deleted at time T.

[0081]IT is calculated using the following (Equation b).

IT=Min (WT+W'T-1, Pj, V-CT-1) (Equation b)

[0082]That is, the smallest value from among (WT+W'T-1),
Pj, and (V-CT-1) is IT. Pj is the value obtained by
multiplying the point-in-time interval from time (T-1) to time T (for
example, the data acquisition interval) by the amount of journals capable
of being written to the journal storage extent per unit of time (that is,
journal write performance (for example, the unit is MB/second)).
(V-CT-1) denotes the amount of free capacity in the journal storage
extent. V is the storage capacity of the journal storage extent.
(WT+W'T-1) denotes the amount of journals capable of being
written to the journal storage extent. More specifically, WT is the
total amount of write-data received from the host computer 400 between
time (T-1) and time T, and W'T-1 is the total amount of unsaved
journals, which were not written to the journal storage extent from time
(T-2) to time (T-1). Incidentally, W'T is calculated using the
following (Equation c).

W'T=(WT+W'T-1)-IT (Equation c)

[0083]OT is calculated using the following (Equation d).

OT=Min (Max (0,CT-1+IT-H),PD) (Equation d)

[0084]That is, the minimum value from among the maximum value of O and
(CT-1+IT-H), and PD is OT. H is a threshold, which is
compared against the amount of stored journals, and when the amount of
stored journals exceeds H, the excess amount of journals (that is, the
quantity of journals denoted by (CT-1+IT-H)) is reflected in
the base data. PD is journal deletion performance, and is defined as
follows:

[0085](when Pj≦PB)

PD=PJ-IT

[0086](when PJ>PB)

PD=Min (PJ-IT, PB)

[0087]That is, when PJ>PB, the minimum value of
(PJ-IT) and PB is PD. PB is the value obtained
by multiplying the point-in-time interval from time (T-1) to time T (for
example, the data acquisition interval) by the amount of data capable of
being written to the base data storage extent per unit of time (that is,
base data write performance (for example, the unit is MB/second)). The
values for journal write performance and base data write performance can
utilize the input/output performance recorded in a performance
information management table 327, which will be explained below using
FIG. 10.

[0088]FIG. 4 shows an example of the results of plotting the amount of
stored journals at time T and the write-amount of write-data (value
assumed to be the journal write-amount) at the respective point-in-time
intervals (for example, data acquisition intervals). To calculate the
data protection period at time T, the write-amounts at each of the
point-in-time intervals going back from time T are totaled, and the time
TD at which the total value reaches the amount of stored journals
CT of time T is determined. The data protection period at time T
constitutes the period from time TD to time T. In other words,
TD is the oldest time for data recoverable at time T.

[0089]FIG. 5 shows an example of the results of plotting a data protection
period in the CDP backup configuration determined in this way on a time
line. The example of FIG. 5 shows that the data protection period changes
over time, and that the minimum value thereof is three days, and the
maximum value is five days.

[0090]If a data protection period for the fixed-time backup configuration
has been computed, and a data protection period for the CDP backup
configuration has been estimated, the data analysis program 323
calculates a value, other than a data protection period, for each
determination item described in the determination criteria management
table 325. In the determination criteria management table 325 example of
FIG. 6, determination items other than the data protection period include
recovery point continuity, backup capacity, and data protection period
fluctuation range.

[0091]As used here, recovery point continuity signifies the interval
between a recovery-possible point in time in the past, that is, a
recovery point, and the subsequent recovery point. For example, according
to the time-line transitions of the data protection period in the
fixed-time backup configuration illustrated in FIG. 3, because a new
generation of backup data is acquired every other day, the recovery point
interval is one day. Conversely, in the CDP backup configuration, since
the source data at all the points in time at which data write processing
has ended is recoverable, the recovery point interval is the minimum unit
of time (in this embodiment, seconds). Therefore, the data analysis
program 323 calculates recovery point continuity as one day for the
fixed-time backup configuration, and as one second for the CDP backup
configuration.

[0092]Backup capacity denotes the storage capacity required for storing
backup data (replicated data in the fixed-time backup configuration, and
base data and journals in the CDP backup configuration) of source data
(protection-targeted data) in a data storage extent 120. For example,
according to the replicated data management table 135 shown in FIG. 2, in
order to retain three backup generations for a 100 MB data storage extent
120, a backup capacity of 100 MB×3=300 MB is needed. Conversely, in
the CDP backup configuration, the storage capacity, which was taken into
account in the computation of the above-described estimate (more
specifically, a total storage capacity of 300 MB, since there is a 100 MB
base data storage extent and a 200 MB journal storage extent) is required
as the backup capacity. Therefore, the data analysis program 323
calculates 300 MB as the backup capacity for the fixed-time backup
configuration, and calculates 300 MB for the CDP backup configuration as
well.

[0093]The data protection period fluctuation range is the difference
between the maximum and minimum data protection period. For example,
according to the example for the fixed-time backup configuration shown in
FIG. 3, one day, which is the difference between the maximum data
protection period of three days and the minimum data protection period of
two days, is the data protection period fluctuation range. Conversely,
according to the example for the CDP backup configuration shown in FIG.
5, two days, which is the difference between the maximum data protection
period of five days and the minimum data protection period of three days,
is the data protection period fluctuation range. Therefore, the data
analysis program 323 calculates the data protection period fluctuation
range as one day for the fixed-time backup configuration, and as two days
for the CDP backup configuration.

[0094]The determination criteria management table 325 retains elements,
which form the bases for calculating scores for determination items, for
each determination item deemed useful for the user to determine whether
or not it is appropriate to migrate from the existing backup
configuration to a different backup configuration. More specifically, in
the determination criteria management table 325, determination items,
which constitute target parameters for making a determination, are
recorded in field 3250, criteria values for the respective determination
items are recorded in field 3251, determination criteria for the
respective determination items are recorded in field 3252, and weighting
coefficients for the respective determination items are recorded in field
3253. The weighting coefficient is used when the migration determination
program 324 carries out scoring for the respective determination items.
The weighting coefficients for the respective determination items, for
example, are allocated such that totaling all of the weighting
coefficients for all of the determination items equals 1, and the larger
the weighting coefficient, the higher the priority of the determination
item corresponding thereto.

[0095]For example, in the example shown in FIG. 6, there are four
determination items: "data protection period", "recovery point
continuity", "backup capacity" and "data protection period fluctuation
range", and the weighting coefficient for "data protection period" is
0.4. In this example, it is clear that the weighting coefficient 0.4 is
the largest value among the determination items, and that the
determination item "data protection period" has the highest priority.

[0096]The user need not input at least one of the determination item,
criteria value, determination criteria and weighting coefficient. In this
case, values calculated for the existing backup configuration can be
recorded in the determination criteria management table 325 for the
respective determination items. This is so the user can easily determine
the advantages and disadvantages of migrating to the CDP backup
configuration by comparing the values in the existing backup
configuration against the values in the CDP backup configuration.
Further, the merit, in this case, is that the burden on the user is
lessened since the user need not make an input.

[0097]However, it is not always necessary to eliminate the need for a user
input, and at least one of the determination item, criteria value,
determination criteria and weighting coefficient is inputted by the user.
More specifically, for example, the user can input at least one of the
determination item, criteria value, determination criteria and weighting
coefficient via a GUI (Graphical User Interface) displayed on the output
device 330 of the management computer 300 as shown in the example of FIG.
7.

[0098]FIG. 7 is one example of a determination criteria input screen. The
determination criteria input screen is for inputting values related to
criteria for the user to determine the propriety of a backup
configuration migration. According to FIG. 7, for example, there is a
field 050 for inputting the identifier of a data storage extent storing
protection-targeted data (source data), a field 051 for inputting the
criteria value of a data protection period (for example, two days) and a
determination criteria (for example, larger is better), a field 052 for
inputting a criteria value for recovery point continuity (for example,
one day) and a determination criteria (smaller is better), a field 053
for inputting a criteria value for backup capacity (for example, 300 MB)
and a determination criteria (for example, smaller is better), and a
field 054 for inputting a criteria value for the data protection period
fluctuation range (for example, two days) and a determination criteria
(for example, smaller is better). Further, the determination criteria
input screen has an execution button 055, which the user presses to
register an inputted criteria value and determination criteria, and a
cancel button 056, which the user presses to cancel an inputted criteria
value and determination criteria. When the execution button 055 is
pressed, the migration determination program 324 registers the criteria
value and determination criteria inputted for each determination item in
the determination criteria management table 325. Furthermore, the
determination criteria input screen of FIG. 7 is an example, and there is
no need to limit the type of configuration and displayed information to
this example (for example, a weighting coefficient can also be inputted
for each determination item).

[0099]The migration determination program 324 references the determination
criteria management table 325, acquires the value calculated by the data
analysis program 323 for each determination item, and performs scoring
for a determination item based on the acquired values, and the criteria
values, determination criteria and weighting coefficients recorded in the
determination criteria management table 325.

[0100]An example of scoring will be explained below by referring to FIG.
8. FIG. 8 shows the flow of scoring for one determination item for which
the determination criteria is greater than the criteria value (that is, a
determination item for which a larger value is better).

[0101]Here, any of three integers, "0", "1" or "2" is assigned as a score
for one determination item. It is assumed that "A" is the calculation
result (for example, the data protection period) of the fixed-time backup
configuration, and that "B" is the calculation result (for example, the
data protection period) of the CDP backup configuration for the
determination item.

[0102]In FIG. 8, when both A and B satisfy the respectively corresponding
criteria value and determination criteria (Step 040: YES), the migration
determination program 324 compares A and B to one another (Step 041). If
the result is that the two values are equal, the migration determination
program 324 assigns a score of "1" to each of A and B, if the result is A
is larger than B, the migration determination program 324 assigns a score
of "2" to A and a score of "1" to B (this kind of scoring is also done
when A is smaller than B for a determination item for which the
determination criteria is the criteria value or less), and if the result
is that A is smaller than B, the migration determination program 324
assigns a score of "1" to A and a score of "2" to B. Conversely, if
either one of A or B does not satisfy the criteria value (Step 040: NO),
when A satisfies the criteria value and the determination criteria (Step
041: YES), the migration determination program 324 assigns a score of "1"
to A, and a score of "0" to B. When A does not satisfy the criteria value
(Step 041: NO), but B does satisfy the criteria value (Step 043: YES),
the migration determination program 324 assigns a score of "0" to A, and
assigns a score of "1" to B. When B does not satisfy the criteria value
(Step 043: NO), the migration determination program 324 assigns a score
of "0" to both A and B.

[0103]The sum of the values obtained by multiplying the weighting
coefficient by the score calculated for each determination item is
calculated for both the fixed-time backup configuration and the CDP
backup configuration. That is, this sum is calculated using (Equation i)
below. The X represents the respective determination items listed in the
determination criteria management table 325.

[0104]The final scores for each of the fixed-time backup configuration and
the CDP backup configuration, score for each determination item, and
backup performance calculated for each determination item (data
protection period, recovery point continuity, backup capacity, and data
protection period fluctuation range) calculated as described hereinabove
are displayed side-by-side by backup configuration on the output device
330 of the management computer 300 by the migration determination program
324 (for example, see FIG. 12). Consequently, the user can easily
determine whether or not it is appropriate to migrate from the existing
fixed-time backup configuration to the CDP backup configuration. This
will be explained in more detail below.

[0105]Look at FIG. 1 again. The monitoring information management table
326 records the management information comprised in the monitoring data
acquisition request sent to the storage system 100 via the management
information input/output program 321. FIG. 9 shows an example of the
monitoring information management table 326. In the monitoring
information management table 326, the identifiers of the data storage
extents 120 targeted for monitoring are recorded in field 3260, the
monitoring period for each data storage extent 120 is recorded in field
3261, and the data acquisition interval for each data storage extent 120
is recorded in field 3262. According to the example of FIG. 9, data
storage extent 00:01 has a monitoring period of two days, and a data
acquisition interval of 15 minutes. These parameters can be defined
beforehand by the user.

[0106]The performance information management table 327 manages information
related to the input-output performance of replicated data storage
extents 121 inside the storage system 100, and is prepared for each data
storage extent 120. FIG. 10 shows an example of the performance
information management table 327. In the performance information
management table 327, the identifiers of the replicated data storage
extents are recorded in field 3270, and the input/output performance of
each replicated data storage extent is recorded in field 3271.
Furthermore, there is no need to restrict conditions, such as the
write-data length on which the input/output performance is premised. The
input/output performance recorded in this table 327 can be applied as the
above-mentioned journal write performance or base data write performance.
For example, when it is assumed that replicated data storage extent 0A:01
is the base data storage extent, base data write performance is 30 MB/s
(MB per second), and when it is assumed that replicated data storage
extent 0A:02 and 0A:03 are both journal data storage extents, journal
write performance is either 30 MB/s or 40 MB/s (for example, when there
are two kinds of journal write performance like this, the smaller
performance value is adopted as the basis for PJ.).

[0107]Operating the above-describe computer system makes it possible for
the user to easily determine if the fixed-time backup configuration or
CDP backup configuration is appropriate for the relevant computer system.
The flow of processing carried out in this embodiment will be explained
using FIG. 11.

[0108]First, the management computer 300 receives in accordance with a
user input operation a determination support request (a request to
support a determination as to whether or not migrating the backup
configuration is appropriate), which specifies a data storage extent
identifier (Step 01). This triggers the data collection program 322 to
make a monitoring data acquisition request comprising the specified data
storage extent identifier and management information corresponding
thereto (the monitoring period and data acquisition interval acquired
from the monitoring information management table 326), and to issue this
monitoring data acquisition request to the storage system 100 by way of
the management information input/output program 321 (Step 02).

[0109]In the storage system 100, the management information input/output
program 131 receives the monitoring data acquisition request, and
transfer this request to the data input/output monitoring program 134.
The data input/output monitoring program 134 acquires data input/output
information (the write-amount for each data acquisition interval) and
replicated data acquisition time for the specified data storage extent
120 in the monitoring period comprised in the monitoring data acquisition
request (for example, the monitoring period that has the time at which
this monitoring data acquisition request was received as the start time)
(Step 03). The data input/output monitoring program 134 sends to the
management computer 300 at a certain timing (for example, either
regularly, or when the monitoring period ends) the data input/output
information and configuration information comprising the replicated data
acquisition time (for example, the information recorded in the replicated
data management table 115 for the specified data storage extent 120 (the
storage capacity of the data storage extent, and the identifiers and
storage capacities of the respective replicated data storage extents))
(Step 04).

[0110]In the management computer 300, the management information
input/output program 321 receives the data input/output information and
replicated data acquisition time, and the data analysis program 323 uses
this information to calculate the backup performance (the data protection
period, recovery point continuity, backup capacity, and data protection
period fluctuation range) for each determination item recorded in the
determination criteria management table 325 for both the fixed-time
backup configuration and the CDP backup configuration (Step 05). Then,
the migration determination program 324 calculates the score for each
determination item and calculates the final score for both the fixed-time
backup configuration and the CDP backup configuration, and displays a
screen (for example, the screen illustrated in FIG. 12) displaying the
calculation results for both the fixed-time backup configuration and the
CDP backup configuration side by side (Step 06).

[0111]The user can recompute these scores at this time by changing the
criteria values and/or the determination criteria (for example, the
backup capacity) for the CDP backup configuration (Step 10: YES). More
specifically, for example, the current backup capacity for the CDP backup
configuration is 300 MB, the same as the backup capacity of the
fixed-time backup configuration, but the user can command the data
analysis program 323 to input a smaller (or larger) backup capacity than
this, and recompute the backup performance for the respective
determination items for the CDP backup configuration. In this case, the
data analysis program 323 assumes both the storage capacity of the base
data storage extent and the storage capacity of the journal storage
extent based on the inputted backup capacity and the storage capacity of
the data storage extent, and computes the backup performance for the
respective determination items (data protection period and so forth). By
so doing, for example, if the backup performance satisfies the criteria
value and determination criteria for a user-emphasized determination item
from among the plurality of determination items for the CDP backup
configuration, the user can learn whether or not satisfying the criteria
value and determination criteria for this emphasized determination item
is sustainable even if the backup capacity is reduced (or increased),
thereby enabling the construction of a CDP backup configuration that is
more in line with the user's needs. Furthermore, for example, the
pre-change computation results for the criteria values and/or
determination criteria (the backup performance and score for each
determination item, and the final scores) can be displayed alongside the
post-change computation results for the criteria values and/or
determination criteria at this time. Consequently, the user can readily
determine which criteria value and/or determination criteria are better
for the CDP backup configuration.

[0112]When the user looks at the displayed screen, and decides to migrate
from the fixed-time backup configuration to the CDP backup configuration
(Step 07: YES), the user commands the management computer 300 to migrate
the backup configuration. The migration determination program 324, in
response to the command from the user, issues a migration indication (for
example, a migration indication comprising the respective identifiers of
the base data storage extent and the journal storage extent) to the
storage system 100 (Step 08), and the storage system 100 receives this
indication (Step 09). Thereafter, the migration from the fixed-time
backup configuration to the CDP backup configuration can be carried out
in the storage system 100 in accordance with this migration indication,
and this migration does not have to follow a specific processing flow.

[0113]Furthermore, when the user decides not to migrate the backup
configuration, and inputs this decision to the management computer 300
(Step 07: NO), this processing ends.

[0114]The above processing flow will be explained in more detail using a
specific example.

[0115]When a determination support request is inputted using the input
device 340 of the management computer 300, a monitoring data acquisition
request is issued from the management computer 300 to the storage system
100. The monitoring data acquisition request, for example, comprises the
identifier of monitoring-targeted data storage extent "00:01", a
monitoring period of "two days" and a data acquisition interval of "15
minutes" (Refer to FIG. 9).

[0116]In the relevant monitoring period (two days), data input/output
information and the replicated data acquisition time are sent to the
management computer 300 either every data acquisition interval, or
subsequent to the end of the relevant monitoring period. Further, the
storage system 100 sends information related to the fixed-time backup
configuration for the data storage extent 00:01, more specifically,
information recorded in the replicated data management table 135 for the
data storage extent 00:01 (that is, the information shown in FIG. 2) to
the management computer 300.

[0117]First, the data analysis program 323 calculates the data protection
period, recovery point continuity, backup capacity, and data protection
period fluctuation range in the existing backup configuration (that is,
the fixed-time backup configuration), and also estimates the data
protection period, recovery point continuity, backup capacity, and data
protection period fluctuation range for the CDP backup configuration. The
calculation results constitute values such as those shown below.

[0121]Accordingly, when scoring is carried out based on the determination
criteria management table of FIG. 6 using the flow of FIG. 8, scores such
as those shown below are obtained for the respective determination items.

[0122]When the final scores are calculated from the above-mentioned
calculation results in accordance with (Equation i), the final score for
the existing fixed-time backup configuration becomes

(1×0.4)+(1×0.3)+(1×0.2)+(1×0.1)=1.0

and the final score for the CDP configuration becomes

(2×0.4)+(2×0.3)+(1×0.2)+(0×0.1)=1.6

[0123]The final scores and score for each determination item calculated
like this can be displayed in the determination support screen, which is
displayed on the management computer 300 as illustrated in FIG. 12. The
determination support screen is the screen on which backup performance
calculation results and the results of scoring are displayed. According
to FIG. 12, the determination items and their priorities (order of the
weighting coefficients) are displayed in the determination support
screen, for example, in a tabular format, and, in addition, the final
scores for both the existing configuration (fixed-time backup
configuration) and CDP backup configuration are displayed. Further, the
backup performance (evaluations) and score for each determination item
are also displayed for both the existing configuration (fixed-time backup
configuration) and CDP backup configuration. Furthermore, the monitoring
period (flow of time) is represented on the horizontal axis, and the data
protection period is represented on the vertical axis, and a line graph
(results plotted on a time line) denoting the transition of the data
protection period for the fixed-time backup configuration, and a line
graph denoting the transition of the data protection period for the CDP
backup configuration are displayed in the determination support screen.
The color of the highest score can be changed, and the superior results
can be highlighted in this determination support screen. By viewing this
determination support screen, for example, the user can determine whether
to retain the existing configuration, or migrate to the CDP backup
configuration simply by comparing the final scores. Either instead of or
in addition to comparing the final scores, it is also possible to
determine whether or not to migrate the backup configuration by comparing
the graphs denoting the transitions of the data protection periods (for
example, the degree of overlap), and comparing the scores corresponding
to the determination items with the highest priority.

[0124]Furthermore, in this first embodiment, the migration determination
program 324 can compare the scores for each of the determination items,
and/or can compare the final scores, either in addition to or instead of
displaying the determination support screen illustrated in FIG. 12, and
can control whether or not migration is carried out in accordance with
the results of these comparisons. For example, when the final score of
the CDP backup configuration is higher than that of the fixed-time backup
configuration, the migration determination program 324 can send a
migration indication to the storage system 100 without querying the user.

Second Embodiment

[0125]A second embodiment of the present invention will be explained
hereinbelow using FIG. 13. The differences with the first embodiment will
mainly be explained at this time, and explanations of points in common
with the first embodiment will be either simplified or omitted.

[0126]In the second embodiment, as was explained above, the CDP backup
configuration has already been constructed in the storage system 100 as
the existing backup configuration, and a determination is made as to
whether it is appropriate to migrate from the CDP backup configuration to
the fixed-time backup configuration.

[0127]FIG. 13 is a diagram showing an example of the constitution of a
computer system in the second embodiment of the present invention.

[0128]This computer system can be the same as the constitution in the
first embodiment with the exception of the points described below. That
is, the storage apparatus 110 has a base data storage extent 122 and a
journal storage extent 123. Program memory 130 stores a CDP program 133
or a CDP management table 136. The CDP program 133 realizes data
protection in the storage system 100 using CDP technology. For example,
the CDP program 133 acquires replicated data (that is, base data) for a
data storage extent 120 at the point in time immediately prior to a CDP
protection-targeted period defined by the CDP management table 136, and
stores this base data in the base data storage extent 122. Further, when
write-data is written to the data storage extent 120 on or after the
relevant base data acquisition time, the CDP program 133 acquires a
journal comprising this write-data, and stores this journal (or the
journal data only) in the journal storage extent 123. Further, upon
receiving a recovery request from either the host computer 400 or the
management computer 300, the CDP program 133 recovers data at a specified
time by reflecting, from among the unreflected journals, in order in the
base data journals from the journal having the oldest time until the
journal at the specified time described in this recovery request.
Further, when the amount of stored journals in the journal storage extent
123 reaches the journal capacity threshold retained in the CDP management
table 136, the CDP program 133 reflects, from among the journals stored
in the journal storage extent 123, in order in the base data journals
from the oldest journal (journal for which the time denoted by the
journal meta data is the oldest) to the journal just under the journal
capacity threshold. The CDP program 133 updates the CDP management table
136 at this time as needed.

[0129]The CDP management table 136 retains CDP-related information
referenced by the CDP program 133. FIG. 14 shows an example of the CDP
management table 136. In the CDP management table 136, the identifiers of
the data storage extents 120 targeted for protection by the CDP
technology are recorded in field 1360, the storage capacities of these
data storage extents 120 are recorded in field 1361, the identifiers of
the base data storage extents 122 corresponding to these data storage
extents 120 are recorded in field 1362, the storage capacities of these
base data storage extents 122 are recorded in field 1363, the acquisition
times of the base data are recorded in field 1364, the identifiers of the
journal storage extents 123 corresponding to these base data storage
extents 122 are recorded in field 1365, the storage capacities of these
journal storage extents 123 are recorded in field 1366, and the journal
capacity thresholds (the above-mentioned threshold H) corresponding to
these journal storage extents 123 are recorded in field 1367.

[0130]In FIG. 13, the data replication program 132 is not shown in the
program memory 130 of the storage system 100, and this program 132 does
not necessarily have to the stored. When not stored, this program 132 can
be installed when migrating to the fixed-time backup configuration. This
is the same as the CDP program 133 not being shown in FIG. 1.

[0131]In this second embodiment, since the existing backup configuration
is the CDP backup configuration, the data analysis program 323 can
calculate the backup performance for the respective determination items
for the CDP backup configuration based on information received from the
storage system 100 (for example, information recorded in the CDP
management table 136). The backup performance for the respective
determination items can be estimated for the fixed-time backup
configuration, for example, based on a replicated data acquisition
interval inputted by the user, and the storage capacity of the data
storage extent in the CDP backup configuration. In this case, for
example, according to the CDP management table 136 shown in FIG. 14,
since the storage capacity of both the base data storage extent 122 and
the journal storage extent 123 is 100 MB for the data storage extent
00:01, the data analysis program 323 can make the backup capacity 200 MB,
which is the total of these storage capacities, and can assume that the
base data storage extent 122 and the journal storage extent 123 are both
replicated data storage extents.

[0132]A number of embodiments of the present invention have been explained
hereinabove, but these embodiments are examples for explaining the
present invention, and do not purport to limit the scope of the present
invention solely to these embodiments. The present invention can also be
put into practice in a variety of other modes.